Click the link:
Enter your Gmail ID into the gmail login box
Click Need Help or forgot password.
Answer the question on the page shown there.
If you find another listed there, click Try a different question.
And then it will ask you to fill out the details like account creation date, subjects of the emails last sent etc.
Try to provide the best possible information to recover your account.
Also, provide them a working alternate email address as contact email address.
Once you provide them all of the information, they will get back to you on your alternate email address.
If you have other queries regarding this or need phone support, please reply back to me the box given below.
And if you can take a second to rate my service(-OK or more -by clicking stars at the top of the page and choose submit), that would be greatly appreciated.